How can I maximize the number of Asterisk channels that can be handled by a single processor?
A. Scaling an Asterisk application larger than 120-channels (four E1’s) or so usually means at least thinking about a multi-processor architecture. Although recent advances in processor power and design improvements in both the Digium and Sangoma interfaces have improved performance and channel capacities beyond this limit, system resiliency should also be considered. In an asterisk environment, if the processor fails, everything stops instantly – all the conversations are cut off and the telecom interfaces go down. A bit of redundancy is cheap insurance. That being said, there are several design considerations to keep in mind when trying to maximize the channel capacity of a single Asterisk box, including: (1) In our experience, one significant processor drain in an asterisk environment is “transcoding” – changing from one voice encoding protocol to another, for example from GSM to aLaw PCM, or vice-versa. So, if bandwidth is cheap, for example in routing a call that arrives from the
